Generally, an electrolytic condenser comprises an electrolytic condenser element formed by winding electrode foils of an anode and a cathode consisting of a film-forming metal, such as alminium, together with a separator, as well as an electrolyte impregnated in the electrolytic condenser element as a driving liquid, which is then sealed in a casing.
The electrolytic condenser is classified into two categories according to allowable voltages, one for low voltages and the other for high voltages. For the latter, boric acid has been used as an electrolyte for formulating the electrolyte liquid.
The electrolyte liquid utilizing boric acid as the electrolyte, however, may produce a large amount of a condensed water (an ester water) due to association of boric acid with the solvent therefor. As a result, evaporation of the condensed water may occur above 100.degree. C. to abnormally increase an inner pressure of the casing, resulting in the risk of opening an explosion-preventive valve and thus in the difficulty for use at the temperature above 100.degree. C. Further, such type of the condenser shows a high specific resistance above 1 k.OMEGA. and varies its capacity considerably depending on the temperature, thereby adversely affecting temperature properties to the large extent.
Accordingly, an object of the invention is to improve the reduction of specific resistance and the temperature properties.